Refine Your Search

Search Results

Viewing 1 to 11 of 11
Technical Paper

Validation Results of Automotive Passenger Compartment and its Air Conditioning System Modeling

2000-03-06
2000-01-0982
This paper describes the development of our software simulation of the car cabin and its air conditioning system. The validation of this software requires a lot of experimental data ( test bench and wind tunnel). The models of this software are based on a physical and parametrical approach. This paper also details the comparison between test and simulation in different operating conditions both the car cabin and the A/C systems. The result obtained from simulation give a good level of accuracy.
Technical Paper

Thermal Energy Storage System by Solid Absorption for Electric Automobile Heating and Air-Conditioning

1995-02-01
950017
The thermochemical energy storage could be a suitable solution for heating and air conditioning electric vehicles. This paper gives the results of a preliminary study engaged to test the STELF process using the metallic chloride/ammonia couple. Among the large number of solid/gas couples available, the MnCl2/NH3 couple features an energy storage capacity of about 180 Wh and 90 Wh per kg of reactive and answers to an automotive application temperature respectively for the heating and the cooling. In winter, the reactor can provide heating to warm the passenger compartment but also to the outer evaporator heat exchanger to avoid the icing up phenomenon. Simulations show the thermodynamic feasibility of the process in the heating, cooling and regeneration modes in order to warm up, air condition and preheat respectively the electric car passenger compartment.
Technical Paper

The Specific Issues of Climate Control in Stop&Go Vehicles

2002-07-09
2002-01-2225
The arising “Stop&Go” function contributes to the reduction of new cars fuel consumption. However, as the engine shuts off when the car stops, cabin heating and air conditioning cut off because they are belt driven. This paper first describes the cabin temperature evolution when it occurs. It shows that solutions must be found in order to guarantee passenger comfort maintaining. Different concepts are presented, built on fuel, electrical or thermal energy storage. A comparison is provided, showing that the latter should be preferred. The biggest remaining issue for long stops is storage itself.
Technical Paper

Optimization Elements for Externally Controlled Air Conditioning Systems

2001-05-14
2001-01-1733
In order to reduce the fuel overconsumption, new air conditioning systems fitted with externally controlled compressors have been implemented. Their operating principle consists in driving electrically (external control) the compressor displacement in order to adjust the cooling capacity delivered by the A/C system to the cooling capacity required by the passenger compartment. Therefore, it is possible to reduce the mechanical power absorbed by the compressor and by this means, the fuel overconsumption. However, this potential of fuel consumption reduction can be only achieved under the condition that the other components of the A/C system, such as the thermostatic expansion valve (TxV), are well adapted all together in order to fully take advantage of the implementation of such new type of compressors. The paper describes the different possibilities of optimization of the TxV in regard to hunting phenomena.
Technical Paper

Modeling of Automotive Passenger Compartment and Its Air Conditioning System

1998-02-23
980288
Valeo Climate control is developing a software package for the design and simulation of car air-conditioning systems. This software package aims to improve Valeo's response to customer requirements concerning delays for design and sizing car air-conditioning systems performances and cost reduction. Further it shall help to capitalize our competence and expertise on the A/C systems. The comparisons between simulation and tests give a good level of accuracy. The software consists of three modules: A first module for car cabin thermal simulation in dynamic and stationary conditions. A second module for the determination and optimization of the A/C system components. A third module is under development for the dynamic simulation of the A/C system in non-standard operating conditions.
Technical Paper

Improved Automotive A/C Systems Using a New Forced Subcooling Technique

1999-03-01
1999-01-1192
One of the main issue for the development of current automotive air conditioning systems concerns the reduction of the fuel consumption resulting from the A/C absorbed power. This fuel use reduction can be for one part obtained by the means of an A/C systems energetic efficiency improvement. Different technical solutions can be implemented. One of these techniques consists in the optimization, or even the control of the refrigerant subcooling at the outlet of the condenser.
Technical Paper

Experimental Investigation of a Thermal Preconditioning of a Car cabin

2005-05-10
2005-01-2057
This paper presents an experimental investigation of two passive thermal preconditioning technologies, pre-ventilation and solar shields, and a combination of both. A Design of Experiment (DOE) was defined in order to evaluate the influence of several parameters (air mass flow and air diffusion mode, size of the air extractors, location and type of solar shield) on the passengers' thermal comfort on entry into the car cabin and after a short A/C running time (10 min). Results show that solar shields are more efficient than pre-ventilation, which means that radiative heat transfers are more effective than the convective heat transfers, even with high air flows. The type of solar shields together with their location on the windows is also influential. After preconditioning, 10 minutes of air conditioning might reduce the air temperature at face level of the front passengers, compared to a non preconditioned car cabin.
Technical Paper

Energy Efficient R744 A/C System Thanks to Torque Estimation

2005-05-10
2005-01-2040
From 10 years, Valeo Climate Control leads R&D efforts to reduce green-house effect emissions due to automotive A/C systems. This paper deals with the development of an alternative A/C system using R744 refrigerant as the lowest Global Warming Potential refrigerant (GWP = 1) to replace existing R134a (GWP = 1300) technology. The paper will show main aspects of the new technology developed for alternate refrigerant and then will focus on control strategy for the A/C system which is a key point for thermodynamic cycle efficiency using R744. Firstly the R744 A/C system used for this study will be described, the concept of maximum COP high pressure linked to optimized R744 thermodynamic cycle will be explained, and the high pressure control strategy will be presented. Secondly the control optimization for the gas cooler fan will also be explained in order to reduce the electrical consumption.
Technical Paper

A Model of Energetic Interactions Between a Car Engine, the Cabin Heating System and the Electrical System

2002-07-09
2002-01-2224
Reduction of internal combustion engines fuel consumption is permanently researched. It leads automotive companies towards global energetic simulation tools to describe the interactions between the engine and the energy consumer systems. Valeo with the EMN Department of Energetic, develop a vehicle energy management tool. It will be able to describe the interactions between: engine, the car cabin heating system, electrical systems and other energy consumers (additional heating system, air conditioning system) implied in the vehicle operation. The first results given by the simulation model have approached quite accurately, the coolant loop warm-up curve, measured during a vehicle test in wind tunnel. The model solves the energy balance on the oil and coolant loops and computes: the heat flux from engine to coolant, the distribution of coolant flows in branches, the thermal exchanges involved in the heater core, the cooling radiator and the oil cooler.
Technical Paper

A Comparison Between Climate Control Systems Providing Thermal Comfort during Vehicle Stops

2003-03-03
2003-01-1073
Expanding the temporal scope of air conditioning in cars is an important customer expectation. It must be available when the engine is off for climate control purposes (during “stop&start” operations or short parking) or for thermal comfort preparation (cabin pre-cooling). Different technical solutions can be classified according to the kind of energy storage they are based on. Regarding stop&start, many solutions are possible. The selection should be made in accordance with the hybridisation level of the vehicle. For parking cooling and pre-cooling, weight is the main issue. Thermal storage or electrical batteries can be used, but tens of kilograms are required. Auxiliary power units would be necessary to obtain full comfort in these conditions.
Technical Paper

42 V Electric Air Conditioning Systems (E-A/CS) for Low Emissions, Architecture, Comfort and Safety of Next Generation Vehicles

2001-08-20
2001-01-2500
Electrical Air Conditioning Systems for 42 V vehicles will provide many benefits in terms of Environment protection, car Architecture, cabin Comfort and overall Safety. E-A/C Systems essentially differ from conventional ones by the use of electrical compressors. First of all, they will be particularly well adapted to new powertrains, helping to make them more environmentally friendly. Accurate control and high efficiency under the most common thermal conditions will reduce the A/C impact on fuel consumption. Besides, higher sealing integrity will cut emissions of refrigerant during normal operation and maintenance. Secondly, the use of an electrically driven compressor (EDC) will suppress a belt, and will reduce the packaging constraints. This will help to design new vehicle architectures. Thirdly, the electrification of air conditioning will allow better thermal comfort. In particular, E-A/C Systems provide a good opportunity for cabin pre-conditioning.
X